Trying to make a pie menu with custom operator
Register the operator class


Register the operator class.  The bl_idname needs to be in all
lower case, with one period. Blender 2.8 is a lot stricter on this
and must follow the naming convention between class and operator eg
OBJECT_OT_MyOperator and object.myoperator  [Links]
The operator returns a set that contains one of ('RUNNING_MODAL',
'CANCELLED', 'FINISHED', 'PASS_THROUGH', 'INTERFACE')  in this case
{'FINISHED'} which is a set as indicated by the curly braces.


Amended code.

import bpy
from bpy.types import Menu, Operator

# spawn an edit mode selection pie (run while object is in edit mode to get a valid output)

class HyperBevel(Operator):
    bl_idname = "hyper.bevel"
    bl_label = "HyperBevel"

    def execute(self, context):
        bpy.ops.object.editmode_toggle()
        --- removed for brevity ---
        bpy.ops.object.modifier_move_up(modifier="Bevel")
        return {'FINISHED'}

class VIEW3D_PIE_template(Menu):
    # label is displayed at the center of the pie menu.
    bl_label = "Operators"

    def draw(self, context):
        layout = self.layout

        pie = layout.menu_pie()
        pie.operator("hyper.bevel")


def register():
    bpy.utils.register_class(VIEW3D_PIE_template)
    bpy.utils.register_class(HyperBevel)


def unregister():
    bpy.utils.unregister_class(HyperBevel)
    bpy.utils.unregister_class(VIEW3D_PIE_template)


if __name__ == "__main__":
    register()

    bpy.ops.wm.call_menu_pie(name="VIEW3D_PIE_template")